Build NGINX Image Filter Module on Alpine Linux

In this article we will build the image filter module as a dynamic module and add to the NGINX base image. The image filter module is used to resize images on the fly.

Dockerfile

FROM nginx:1.27.0-alpine3.19-slim as base

FROM base as builder

# Install build dependencies
RUN apk add --no-cache --virtual .build-deps \
  gcc \
  libc-dev \
  make \
  linux-headers \
  curl \
  gd-dev \
  pcre-dev \
  zlib-dev

# Download and extract nginx source code
RUN mkdir -p /usr/src \
  && curl -fSL http://nginx.org/download/nginx-${NGINX_VERSION}.tar.gz | tar -zxC /usr/src

RUN cd /usr/src/nginx-${NGINX_VERSION} \
  && ./configure \
    --with-compat \
    --with-http_image_filter_module=dynamic \
  && make modules

# Add module to base image
FROM base as nginx-image-filter

RUN apk add gd # Image filter module depends on gd

COPY --from=builder /usr/src/nginx-${NGINX_VERSION}/objs/*.so /etc/nginx/modules/

Build

docker build -t nginx-image-filter .

Usage

Configuration

load_module modules/ngx_http_image_filter_module.so;

events {}

server {
  listen 80;
  server_name localhost;

  location / {
    root /usr/share/nginx/html;
  }

  # Enable image filter for images
  location  ~ "^/images/.*\.(jpe?g|png)$" {
    image_filter resize 100 100;
  }
}

Run

This example mounts the nginx.conf file and images directory to the container.

docker run -p 80:80 \
  -v ./nginx.conf:/etc/nginx/nginx.conf:ro \
  -v ./images:/usr/share/nginx/html/images:ro \
  nginx-image-filter